Belt tension extremely tight at 85-90Hz - can't side extruder without force - failed calibration - Hardware, firmware and software help

RE: Belt tension extremely tight at 85-90Hz - can't side extruder without force - failed calibration

Jonkeegan — Tue, 05 Aug 2025 20:35:14 +0000

Yes this was the problem! Thank you. I had the pulley inverted on the X axis motor. Can't thank you enough!

RE: Belt tension extremely tight at 85-90Hz - can't side extruder without force - failed calibration

Jürgen — Fri, 01 Aug 2025 15:16:44 +0000

It looks like, when the print head should be moving purely to the right end stop, it is also moving forward a bit. So the two motors and belts are not moving in sync.

Are you really sure the motor pulleys are seated correctly? Left pulley needs to be installed with the toothed side up, smooth side and grub screw down -- right pulley the other way round, with the toothed side down. You can see them through the hexagonal holes in the motor mounting blocks.

RE: Belt tension extremely tight at 85-90Hz - can't side extruder without force - failed calibration

Jonkeegan — Fri, 01 Aug 2025 01:12:35 +0000

IMG_2449-small

Ok since this post, I had to order replacement left belt tensioner, and take half the printer apart. I carefully followed the docs, and made sure the pulley and belts were all correct. I was able to get the printer to pass calibration tests last night, and had a terrible print. Today I went to re-tension the belts and it is now failing calibration. Here's a video of the auto home crashing and rebooting the printer. I tuned and re-tuned these belts but still having probelms

RE: Belt tension extremely tight at 85-90Hz - can't side extruder without force - failed calibration

Michael — Sat, 26 Jul 2025 20:42:30 +0000

Double check the orientation of the pulleys on the x and y motors with the build guide. Make sure they are opposite. That is the teethed part is on the bottom of the spindle for one motor and the top for the other. If they are wrong it makes the gantry difficult to move

Belt tension extremely tight at 85-90Hz - can't side extruder without force - failed calibration

Jonkeegan — Sat, 26 Jul 2025 18:57:53 +0000

Frustrating problem. Everything assembled, belts tuned to 85Hz, belts look to be on pulleys ok, but the tension feels REALLY tight. I am used to being able to slide the extruder on X axis without much force when motors turned off on my older printers, but this took a lot of effort. But the tuning seemed correct. Failed Y calibration. Just kept going back and forth on X axis then failed / rebooted.

In my effort to adjust belt tension, the nut slipped on left belt tensioner, so waiting for replacement part for that now.

I'm going to redo the belt threading and fastening to the mount but was pretty stumped as to what was going on. Thanks!